lib/Transforms/IPO/InlineAlways.cpp

   1 //===- InlineAlways.cpp - Code to inline always_inline functions ----------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements a custom inliner that handles only functions that
  11 // are marked as "always inline".
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #define DEBUG_TYPE "inline"
  16 #include "llvm/CallingConv.h"
  17 #include "llvm/Instructions.h"
  18 #include "llvm/IntrinsicInst.h"
  19 #include "llvm/Module.h"
  20 #include "llvm/Type.h"
  21 #include "llvm/Analysis/CallGraph.h"
  22 #include "llvm/Analysis/InlineCost.h"
  23 #include "llvm/Support/CallSite.h"
  24 #include "llvm/Transforms/IPO.h"
  25 #include "llvm/Transforms/IPO/InlinerPass.h"
  26 #include "llvm/ADT/SmallPtrSet.h"
  27
  28 using namespace llvm;
  29
  30 namespace {
  31
  32   // AlwaysInliner only inlines functions that are mark as "always inline".
  33   class AlwaysInliner : public Inliner {
  34     // Functions that are never inlined
  35     SmallPtrSet<const Function*, 16> NeverInline;
  36     InlineCostAnalyzer CA;
  37   public:
  38     // Use extremely low threshold.
  39     AlwaysInliner() : Inliner(ID, -2000000000) {}
  40     static char ID; // Pass identification, replacement for typeid
  41     InlineCost getInlineCost(CallSite CS) {
  42       return CA.getInlineCost(CS, NeverInline);
  43     }
  44     float getInlineFudgeFactor(CallSite CS) {
  45       return CA.getInlineFudgeFactor(CS);
  46     }
  47     void resetCachedCostInfo(Function *Caller) {
  48       CA.resetCachedCostInfo(Caller);
  49     }
  50     void growCachedCostInfo(Function* Caller, Function* Callee) {
  51       CA.growCachedCostInfo(Caller, Callee);
  52     }
  53     virtual bool doFinalization(CallGraph &CG) {
  54       return removeDeadFunctions(CG, &NeverInline);
  55     }
  56     virtual bool doInitialization(CallGraph &CG);
  57     void releaseMemory() {
  58       CA.clear();
  59     }
  60   };
  61 }
  62
  63 char AlwaysInliner::ID = 0;
  64 INITIALIZE_PASS(AlwaysInliner, "always-inline",
  65                 "Inliner for always_inline functions", false, false);
  66
  67 Pass *llvm::createAlwaysInlinerPass() { return new AlwaysInliner(); }
  68
  69 // doInitialization - Initializes the vector of functions that have not
  70 // been annotated with the "always inline" attribute.
  71 bool AlwaysInliner::doInitialization(CallGraph &CG) {
  72   Module &M = CG.getModule();
  73
  74   for (Module::iterator I = M.begin(), E = M.end();
  75        I != E; ++I)
  76     if (!I->isDeclaration() && !I->hasFnAttr(Attribute::AlwaysInline))
  77       NeverInline.insert(I);
  78
  79   return false;
  80 }